Various methodologies have been developed to provide networked storage systems. In Direct Attached Storage (DAS) systems, a server is directly connected to storage devices such that data on the storage devices are only accessible through the one server. A disadvantage of this system is that if the server is malfunctioning or is off-line, data on the storage devices cannot be accessed. In Network Attached Storage (NAS) systems, a server is located on the front-end of a network to assist in file storage, often in addition to a DAS server. The storage availability of an NAS server is independent of the DAS server. Since an NAS server is located on the front-end of a network, it has the disadvantages of sharing the network bandwidth and being affected by increased network traffic and bottlenecks.
FIG. 1 is a block diagram of a prior art embodiment of an electronic network system including a storage area network (SAN) 124. In SAN systems, storage devices 126, 128, 130, 132 are connected to servers 118 through a separate back-end network. SAN 124 typically includes a number of switches connecting multiple servers to multiple storage devices so that each server may access the data on each storage device. Additional storage devices and servers may be accommodated by adding more switches to SAN 124; however, increasing the number of switches in SAN 124 increases the number of hops data must pass through before reaching its destination, which increases latency within SAN 124. A configuration containing tens to hundreds of switches is difficult to manage and troubleshoot. If a fault occurs, technicians may spend hours trying to identify and replace the faulty device.
As shown in FIG. 1, storage devices such as RAID 126 (Redundant Array of Independent Disks) are accessible only through SAN 124 and server 118. During large file transfers, the computing power of server 118 can be tied up performing simple store-and-forward operations while other perhaps more computationally intensive operations must wait. File transfers between storage devices as well as transfers between a storage device and an Internet Protocol (IP) switch 116 must pass through one of the servers.
The servers and various types of storage devices connected by SAN 124 may use several different communication protocols, particularly when new storage devices are added to a legacy storage network. For example, server 118 may communicate using an Ethernet protocol while Just a Bunch of Disks (JBOD) 128 communicates using a Fibre Channel (FC) protocol. Protocol conversions are typically non-trivial operations since many protocols, like IP over Ethernet and Fibre Channel (FC) have no common layers.